Expression of tryptophan 5‐hydroxylase gene during sea urchin neurogenesis and role of serotonergic nervous system in larval behavior
Expression of tryptophan 5‐hydroxylase gene during sea urchin neurogenesis and role of serotonergic nervous system in larval behavior
复制标题
DOI：
10.1002/cne.10865
复制
发表时间：
2003-11
影响因子：
2.5
通讯作者：
S. Yaguchi;H. Katow
中科院分区：
文献类型：
--
作者：
S. Yaguchi;H. Katow
色氨酸5-羟化酶（TPH）是血清素生物合成的限速酶。对TPH进行了cDNA克隆，并通过酪酰胺信号放大（TSA）技术和Northern杂交进行原位杂交，检测了海胆Hemicentrotus pulcherrimus（HpTPH）幼虫中TPH信息时空转录的发生情况。根据推导的HpTPH氨基酸序列，在系统发育上，海胆在无脊椎动物中与脊椎动物的位置最接近，并且HpTPH在催化结构域中具有共同的保守序列。 HpTPH 转录的起始仅发生在原肠胚晚期，顶神经节 (SAG) 的血清素细胞中，该细胞由一群 HpTPH 阳性细胞和其间的阴性细胞组成。原位杂交显示mRNA表达模式与之前报道的血清素细胞的免疫组织化学定位相似（Bisgrove and Burke [1986] Dev. Growth Differ. 28:557–569; Yaguchi et al. [2000] Dev. Growth Differ. 42:479–488）。对氯苯丙氨酸 (CPA) 是 TPH 活性的不可逆抑制剂，可显着降低血清素细胞中的血清素含量，而 HpTPH 表达模式和时间以及 SAG 细胞的神经纤维延伸显然不受影响，这表明 CPA 只干扰血清素的合成，而不干扰神经系统组织。尽管培养室中发生纤毛跳动，CPA处理的幼虫却不会游泳，这表明适当的血清素合成对于幼虫的正常游泳是必要的。 J.Comp。内罗尔。 466:219–229, 2003。© 2003 Wiley-Liss, Inc.
Tryptophan 5‐hydroxylase (TPH) is the rate‐limiting enzyme in the biosynthesis of serotonin. cDNA cloning of TPH was carried out, and the occurrence of spatiotemporal transcription of TPH message was examined in larvae of the sea urchin, Hemicentrotus pulcherrimus (HpTPH), with in situ hybridization by using the tyramide signal amplification (TSA) technique and Northern hybridization. Based on deduced amino acids sequence of HpTPH, phylogenetically sea urchin locates at the closest position to vertebrates among invertebrates, and HpTPH had common conserved sequences in a catalytic domain. Initiation of HpTPH transcription occurred at the late gastrula stage exclusively in serotonin cells of apical ganglion (SAG) that was composed of a cluster of HpTPH‐positive cells and the negative cells in between. In situ hybridization showed that the mRNA expression pattern was similar to the immunohistochemical localization of serotonin cells reported before (Bisgrove and Burke [ 1986 ] Dev. Growth Differ. 28:557–569; Yaguchi et al. [ 2000 ] Dev. Growth Differ. 42:479–488). p‐Chlorophenylalanine (CPA), an irreversible inhibitor of TPH activity, considerably decreased serotonin content in the serotonin cells, whereas the HpTPH expression pattern and timing, and the extension of neurofibers from SAG cells were apparently unaffected, suggesting CPA exclusively perturbed synthesis of serotonin but not nervous system organization. CPA‐treated larvae did not swim, despite the occurrence of ciliary beating in culture chamber, suggesting that proper serotonin synthesis is necessary for normal swimming of the larvae. J. Comp. Neurol. 466:219–229, 2003. © 2003 Wiley‐Liss, Inc.